When manufacturing casting resin parts out of casting resin, it is necessary to carefully degas each one of the individual casting resin components prior to their mixing, on the one hand, to avoid defects from occurring in the finished casting and, on the other hand, to be able to carry out the casting operation itself without any errors and under the desired pressure conditions. As it is known from the state of the art, the casting resin mass is usually mixed out of at least one resin component and one hardener component, with the components being highly viscous liquids.
The state of the art consists of both discontinuously and also continuously working degassing systems. The casting resin or rather the casting resin components is in both cases guided over a degassing surface with the desire to apply a thin layer of the respective component to the degassing surface. The gas components in the casting resin are removed by the vacuum existing in the housing.
It must be pointed out in this connection that the description hereinafter refers to the degassing of casting resin to simplify the description. The man skilled in the art understands that, as a rule, this concerns the degassing of casting resin components, which have not yet been mixed with one another, for example a resin component or a hardener component.
The discontinuously working methods use systems which include a storage container which is so large that, as a rule, a day's charge is received therein. Degassing takes thereby place in this storage container, from which the respectively needed volume amount is removed for casting of the structural elements. The inside of the storage container is under underpressure during the degassing and during the casting operation. Circulating devices are usually provided in the storage container, which devices are used to distribute the casting resin on a large draining or degassing surface. Sufficient time for the degassing is available with this procedure during the night hours, during which the casting resin is not processed.
When production takes place during several shifts, then it is no longer possible due to the amount of required casting resin, to use the storage containers simultaneously for degassing. Therefore, additional degassing containers are utilized, in which the amount of casting resin needed for production is received and degassed. These degassing containers are mostly set up at a level above the associated storage container so that the degassed material can flow into the storage container. From this results the disadvantage of a high total height. Depending on the shift operation (two shifts or three shifts), it may be necessary to associate several degassing containers with a storage container in order to guarantee a sufficient degassing time for the casting resin. From this results also an occupation of a large amount of space which in turn leads to high costs for the system.
Furthermore, there exists the disadvantage with such systems that, with the apparently advantageous possibility to always add nondegassed material into the storage container as is continuously being removed, the gas content in the stored material increases considerably due to the added nondegassed material, in spite of a continuously running degassing operation. The demands for quality are as a rule no longer met. A bringing of nondegassed material together with the already degassed material must, therefore, be avoided under all circumstances.
It is known in the continuously operating devices to insert in a housing a horizontally arranged, rotatable plate, onto which the casting resin is applied. By rotating the plate, the casting resin is guided radially outwardly so that it can run off downwardly on the inner walls of the housing. The underpressure in the housing brings about the continuous degassing. The disadvantage of these devices is that it is not guaranteed that only the completely degassed product reaches the bottom area of the housing to be further processed from there. Rather, it is possible, for example, by moving too much casting resin onto the rotating plate, for this casting resin to drip downwardly in a nondegassed state. This would result in a mixed product which is not sufficiently degassed.
A cascade degassing is provided in a further device known from the state of the art, in which the casting resin runs cascade-like over several degassing surfaces arranged in the housing. This theoretically enables a fine distribution of the casting resin and a long treatment time. The disadvantage is that it cannot be assured, nor monitored, that the casting resin is distributed in an even layer on the degassing surfaces. Rather a so-called "stream formation" occurs often, during which the casting resin flows in large volume streams downwardly at certain points on the degassing surface. Only an insufficient degassing or none at all takes place at these points for understandable reasons.